Process of manufacturing electric-conduit sections



(N0 Modl.)

J. P. CUMMINGS. PROCESS CI MANUFACTURING ELECTRIC CONDUIT SECTIONS.

No. 497,535. Patented May16,1893.

min/1% s as UNITED STATES PATENT OFFICE.

JAMES F. CUMMINGS, OF DETROIT, MICHIGAN.

PROCESS OF MANUFACTURING ELECTRIC-CONDUIT SECTIONS.

SPECIFICATION forming part of Letters Patent N 0. 497,535, dated May 16,1893. Application filed July 2,1992. Serial inseam. (Nommlehl To allwhom, it may concern/.-

lie it known that I, Janus F. Uumnuos, a citizen of the United States,residing at- Detroit, in the county of \Vayue and State of illichigan,have invented certain new and useful Improvements in Processes of MannfactnrlllLL (mnluit-Sections for Underground Electrical (onductors, ofwhich the following is a specification, reference being had therein tothe accompanying drawings.

This invention relates to a new and useful process of manufacturingconduit sections for undergrcmnd electrical conductors, and theinvention consists in the peculiar manner of manufacturing such aconduit comprising an inner and an outer casing spaced by strips orblocks and having an intervening annular chamber filled with anon-conducting compound forced in in a liquid state and allowed to dryor harden therein, all as more fully hereinafter described.

The article hereinafter described and referred to I have made thesubject matter of a pending application for Letters Patent filed Julyid, 15392, SerialNo. 1,542.

In the drawings, Figure 1 is a view showing the two casings and themanner of engaging one within the other, the outer casing being insection and the inner casing in elevation. Fig. 2 is a longitudinalsection in diagram through the conduit section with a pump applied toforce in the non-conducting mate rial. Fig. 3 is a longitudinal sectionthrough the completed conduit section. Fig. 4 is an end elevation of theinner sect-ion in Fi 1.

Figs. 5 and o are end elevations of sections of modified form.

A is a casing preferablya metallic pipe and l; is a similarcasing orpiping of somewhat smaller diameter than the casing A, these pipes beingof such a size that one may be in scrted within the other and leavebetween the two an annular chamber.

In orderto maintain the inner pipe in proper relation to the outer pipeI employ spacing blocks or strips of any desired construction. Thatwhich I preferably employ consists of a rope (I secured by means of aband or string 1) at one end, and wound spirally around the inner casing13 from end to end and likewise secured at the opposite end. This ropeis of a size so that when it is bound around the casing B it will justfit within the casing A, as shown in Fig. l, leaving a spiral passageway from end to end of the tube between the two casings. To the innercasing A at one end I then apply a plug E and couple upon 'theoutercasing the discharge pipe F from a pump G of any desired construction.This pump has a suction pipe ll connected with a supply ofnon-conducting material, such as asphaltum or similar substance. Thepump being new operated, it is evident that the compound will bedischarged into the annular chamber I between the two casings, and willfollow in the spiral path-way formed by the rope to the opposite end ofthe casing, entirely filling the chamber I. I preferably place a plug .lat the opposite end of the chamber I, which plug will necessarily have avent hole K to allow the air to be forced out iii-advance of thecompound. A plug L is then inserted at the opposite end of the chamber'Iand the section is-allowed to remain until the compound has hardenedinto a solid mass. The resulting section is water tight and cannot leakat any point until both the inner and outer casing together with thefilling in the chamber I has been punctured.

Any desired coupling may be employed in connecting the sections togetherin laying them into a completed conduit.

The reason why I preferably employ the spiral rope is that it forms asingle spiral chamber I from end to end of the casing and insures aperfect and uniform filling of that chamber with thecompound. I may useother spacing devices however, such for instance, as shown in Figs. and0. In Fig. 5 I have shown a series of longitudinal strips M connectedtogether by a cord or other separating device N, and in Fig. (l I haveshown spacing blocks 0, having grooves 1 out at points in the marginthereof. I consider that these constructions are within the spirit of myinvention although I prefer the flexible spiral device which has theadvantages mentioned.

What I claim as my invention is- 1. The herein described process ofinanufactoring conduit sections for electrical conductors consisting inconcentrically arranging two tubes, with spacing blocks between ICOforming spaces from end to end, retaining the tubes in a fixed positionrelativetoeaehother and then in forcing a non-eondueting (7on1- ponndinto the annular space between, and finally allowing the compound toharden sub stantially as described.

2. The herein described process of nianufaeturing eonduit sections forelectrical eonduetors, consisting in spirally winding a easing with anon-conducting flexible cord in serting the casing thus Wound into alarger easing of a diameter equal to that o[ the inner tube and itswinding retaining the tubes in a fixed position relative to each other,tilling one end of the inner tube and then in forcing into the spacebetween 'a liquid non- \Vitnesses:

M. U. OUoouER'rY, N. L. LIN'DOP.

